SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ff367945646ada317b10d7cc504a9d9477e45d538edfc81421b80d5e976a73e' 
  AND token = 'XaKgxnW1j9JFQf+FnDztuiU/N4aYKneOD6Wgz9NxPRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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