SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fa5a282221684797ced6cd468eea4d3ec2ed2020edc6c80e9d3c0d97d3e3c93' 
  AND token = '9q6nSrh7Oz8CarztIZ6ckRSz2EpSQCohvQgHfQP22ao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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