SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f237b6274ac6cc211be8d45d3f438510a16f52ae81f34f526515f570e7d7baa9' 
  AND token = 'H6MpUuBepYbuNnaf4Rlx4U/hYJ9jo8m5B37uD91qLCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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