SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'af6743ca47399f9a554e025bde23e370425f9b246b9e8bf92264901feafcbd70' 
  AND token = 'DKyzouJpAGNp8nINxZ2rv5WaliMwEIe5d77NoHVbOeU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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