SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed1d87cfbba71d17a087ed084812b2f2e8ba5ab76ec5994f4f0507e2968b0adf' 
  AND token = 'OWEtSOBmRgR+0Nw3NDQKIjTgX0k3gvdqgHDETC42mLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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