SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29904596e07d5bbf993d2bd9afea21affe1e805dcd09896b986704fa19e61a3c' 
  AND token = 'jschZhUIEtJQCXD/qGAG8A3Xs8SVNP763BQtUXRsgbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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