SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92a168f4af24c382af6ff4e053a86745f9a63e25fa6ec292a731d8d22c7b9c04' 
  AND token = 'Skz2oRqoL4Bkxv92Ia+lHpn8EUx/+3OBCFXhgV+JCic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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