SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6dd6df22062a98752326641c18548b8be5d0771ef491039e28a2e14d244b50da' 
  AND token = 'iSLbjcQXRE886ge1iofL3HE4NIqX9Yq5KwuuvB4jQa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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