SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4ccf8a155116ec6d7cc47802306abc29b4260ebc8475bb984f96b86fe2acca8' 
  AND token = 'mTEaaabavbvIMFa+DRzqMI9rHYp0814WNwlK91RkBsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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