SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b427afea25df10a6419fcf0767ca8229e1932bc765ff13103c410c3348a81031' 
  AND token = 'ZHQdlrFnOYAmYjBA7vlKLOwkCpYXaDKTx0GAVHZwR5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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