SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b6d1dc198acefbe0b88d5d749d379320575e08635a7eb0b3379ae764880dcb2' 
  AND token = 'ztO9uuHn4fjrWOqmnW9Rj024GnJxfwkBZbUKpQYkkv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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