SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa91d004f405d5323dc9d765ac03ba70bacbb4ca634edb6975586eb4824fc793' 
  AND token = 'TUo3wmohfqujRLDFiLsakMTfL3BMare+fKf2T1dPWhc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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