SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c9f65ed67930431af11d4f2b01df7322bd4bb442d95fdd5316778cd80d15686' 
  AND token = 'iSVvsurP5IdnRPAuMVsLObnF44UVX3BlcROUPFZs30I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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