SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2fc366323093f6a097ddc8e36737cbb91e3a0f639ac91832220ef930f35500d4' 
  AND token = 'eJ08nPkSjC6G2wEA37MgDBG6YeshhZN03lE7xXdSYno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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