SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '919523d425ab2da230dfcf6173d3200b194536e1a3fc91684b7a87e68351f1fc' 
  AND token = 'ZFtoJFLIVbk8slDQ7bC5x8AqYBoUOhHM8ocGY8okhDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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