SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cb25ca1e1c98820f82cc1663091500ae4c1e50c7f2d4285a84eee342374ae24' 
  AND token = '0bDM7c+DxxwJcFMRXDRRvDaAPifQq3bV74BNC8dtSCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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