SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '959a6918471aaa9375d81ca95c090aebe211b6528a796221f2e5d33aadffb8f8' 
  AND token = 'dpIuYx1BqHYc33Z1IzpKkdT1wXfhmisp8ZFcbG5dcwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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