SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db9bc312a3422152e058ba0e26945562dafcda396086335762334732dd62c075' 
  AND token = 'S+R/6OG4jNS56NAwCavGL4Wj9BZ4TnfnKRq5AMBCRBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}