SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90e2edb818529f528c20497b7ce747b5185b9a7bdcb5c751a65ff9f011e5b3a7' 
  AND token = 'N+v1xkdYNJc675MyT+Hg9/CLDUxtudWQ3v0OJGPxsbo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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