SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '857cc244d5d9e9af7256ff52fb2624f92e0fb16687dc52932df0ca3a6be0b0e9' 
  AND token = 'eMKTAAD9aLV+RvBfDJnIYRyKHLD3YdSEefjKy2fFdp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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