SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45f61fbd37d2a807332928e6468d17c5d9dd70e91ded26a91135882116e02e6f' 
  AND token = 'YkFV/1oZncLUiVhRovTwWRXxv4zjmuZNuPCxHV0p3Ew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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