SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '331589abe45310d76b38d704b0965f4fe7b627d625c134b09378753ba9773bf8' 
  AND token = 'cf/SMGccGlyPgbCZeVjqtwNRJB/vPdMmHhKTi9e/cX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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