SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '629737b5772504207b8251ec6b5b431e4d3b33a177b49a372061847e70758c50' 
  AND token = 'krjc0Gkn0E252JGGINWzA4hHYeEAShUy+ZyhyRg+fRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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