SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f4a8567f8a15ae6ae534d5b2490d50e6ca9ec00b5fbd450a98a723fddf1b9e70' 
  AND token = 'OnQ9qQRH6JZntUrsOOn2CoWHI3TpBjlYAubtdUWOPGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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