SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5d57460ca1b24cb02298193056fdd31f886a1c4bb7219b1a73be07624f7938a' 
  AND token = 'MqMWV/cxM+SfeQrc91u0Bcxhsdro4GL641fLYQQ2cjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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