SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd739c0ae93ab7e11fc43627324e97bd4460369220cef9c14b6af2b5538336a91' 
  AND token = 'U7vhvp41ey6cr2gNZER7BJCFaPoEH3gsFTHeRqCtjuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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