SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3c1a9aac2ec6e8a04bf0a9d26b9d16b6745aadfe13a8457a7be61b259faaf05' 
  AND token = 'rvK7sR3UfINd4D6BmA/YejEsro9bD94bOFEqNSQk2Ws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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