SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdf81ee7e1a747693aaa770cd6b3d4edcbe2a54c0abd91ac48d27873e2eaad16' 
  AND token = 'VLm5mJ4p2oLmdajuF72NnTh5C0Vxd0xxGdrpzahjCeQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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