SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd68e7861ff8928f9f77a706cdbc533892fcd533aa469601cf3ca3657beb46510' 
  AND token = 'Uh6eSu9dU6Kqf3vEMybNtKca/UE+GF1u1QOqM+J3Adk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}