SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00759475e176fccf0b692cd857e87da1a488b166dddb629767333a86a4f9fd14' 
  AND token = 'lBICqGVo8qgGD1L3eaMsxHYpb/Zvzl4C70+bL7mKBxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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