SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7bc8c73a339d9415d198982a7caaea81b0ea9d09e6141f79711925a0e5903ae' 
  AND token = 'TfM/od0gcyvdLJBcrbOcx9cd+b+eUO8Mnz8mb6LvARA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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