SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea76d3a067820b0187a93bef6fcd3786d2acfb9f980918a96b3a093362009635' 
  AND token = 'PJI59EqErNw+lTmSK6i1/om/uXAj3xsb3cFYKy83tEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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