SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a49febfc2f811bfdf13975dfb1b36ae881923b6cec587f6a296f9744126a022b' 
  AND token = 'A6gYkq9GP2D5YYgawK4Za4MixyAKj6/+MFL2k6UwQq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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