SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '188c436e37b78c984e9c1836cb84d488b0e584c5d5d216bf7490b55d6d68c8f7' 
  AND token = 'AKIe0rcfXVgWgIgwhq9njYIxiqYBZuKvRUStJaHWRkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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