SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c53e9d89b560973a9e60bcbf31d04f15c1e66b1fbe65da3c416f8bd48219146' 
  AND token = '+bEPTwy1aNGmYtYoLSupqFQILJ/81tisvh58PrwJgkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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