SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c410fbfaf952ae15840ed35b208c5bd3f9173f2ad71589e5a003d669a619bee' 
  AND token = 'VcYAy5fCtJl+FBVcAXh2wOY0WVxnehZGbF8d+HTInfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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