SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99bf35633772703cbd95524b6c4f180d69127e134a0db76e7db151ce90242346' 
  AND token = 'jkj0mkAPAickltHxAoVmVjbcjtUX1KC31a4db16+xcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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