SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5614160e09370c60d62be6396f9a0a51965389b85ae5b8345fbe5f1003d81a67' 
  AND token = 'U6q2BoBLGVxC3wRH+HjCTyUXwyysiIVC/mBqPdlh9tY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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