SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b419d1d77044851500b75b0e9a5a5424e94f8eed5162a553795dd13de4a1f3f' 
  AND token = '/TToBM/m95G4Sye1cYLufVNU/WquMDdSwf0byMVbsOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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