SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15b22332ab2cc5d8ec18f8a4dcbd6e3313568933fef299b8563d4682162790f5' 
  AND token = 'CG3zWG2IatDSwLXqWVfcuDgpx+Pu3oGz83YHOvT3Tq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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