SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '545487281a471d043570026c31483914b1f11a4fbeb984c545e419b01e46e2f6' 
  AND token = 'zWvBJzzjPaqQRh8/E2D4k57kLnifj7Rdn8GaeF1xMRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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