SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1784669b9d470b0fb38cb38f8c656189feb45430a639dc0b6c274ce165ece5eb' 
  AND token = 'Ovl1yZGiaU+UAtHgeDe06J/Wux0Mvo+Vqp8ig9EQIqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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