SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04e0c0be663dc976b0f377b028a6f2ab4da7960b8c4e41d1bba0d3fa479c23b5' 
  AND token = 'RSxwGu4wbHjus0034VPlTIah+NnhYMkelZHSxThihxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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