SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6efe13c52538976d98fc86617277319045b6373c74e66d5694c4bbeee153140a' 
  AND token = '1ZUUyyDLCRO5tfnxndYnR4SGB1d5v4QID2/PxKzS8us=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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