SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5328575881b2b2ab19f4cf01090cae667481011cce63565df4b4e3f8ebd7f65' 
  AND token = 'SNgMfqt+j6JyUQTkYw2PFcJZBshhAYJ6xC1a8XGqJP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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