SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f80ad507e437baee7911a662434243afd1799df29d4fbfcfa6469916b3ef421' 
  AND token = 't5f5r68k8i60p/vrs3IBF3JEMrxP9OSgYOdl4z8Lq1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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