SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b71e7a93905a1fef8144a4b11269bb2a187faa89ca921ddfbf368992dc92baa7' 
  AND token = 'QUe33idyQIIram5ESGg3b12zEQqwdQDKR7d4Vc9jZ5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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