SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39884ae14b6b1749fcbad90845a8095a8371117fda203212031a83c76d8fdb78' 
  AND token = '3JDYTDiFqqGW94oRcd093Naiyx9JLCEH6ePhI1VwJfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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