SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c87d2b90035e1817d9675ad109a7327db8acc8419a58bf438588403a67f68d46' 
  AND token = 'zezg1cH5J2w3F9KAVPFrmPM2ZIo31upWXdOxU/kRcAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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