SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '240c6a6a394530b3e5777f925f79ccfd61aae164f8ca251a88339d7f62ad1b29' 
  AND token = 'z5dWchfhYqBFDu2azzeVC9bo3XfKd+CJWZx26XQLz2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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