SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e344bc69ad148ad78a129acc35f1aecac36a45d9135a4ce59226a9b5ed718970' 
  AND token = 'U0/9ELM/MTzdhT3WIDq7XvEiSLzxdAjsAMjr7KqeXGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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