SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d5d40117817a08a91525f9473bda5bbee20b08910de041be366f064c3268265' 
  AND token = '2jywBjHC9okBn2YsFcRE/trHMh5UKGzvs1uINHvZJbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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