SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f2f229e32c8c5a8789c99df0d9c4f7baf77d685873af1e36f4517861a01311c' 
  AND token = 'z8QBWn6BjiExBMCuSC75uz+8LbpI5h3RD/ZDKiezPSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}