SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4cb5bf4e23beed2795c8578dc3d931e66ac3166205729c1ba1a1d2490263021' 
  AND token = 'HvvWtZxbLmzKCNPZ04UsZuft2cMw1Ae2ktwfAJFSUSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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