SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2dca28470a7b63798f1b254f5dfb0771f01a6afb5fec9f73cfbba6b7cb3e744' 
  AND token = 'HI3Je5ZmrQrsY5w8ACRLqzhZBhov2JAZZGQOlbeKb3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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